Michał Górny · gentoodev-libs/libclc: Use llvm.eclass to obtain correct llvm-config pathUse the newly-introduced llvm.eclass API to obtain the correct path
for the newest LLVM slot including clang, to fix the issue when
first-level 'clang' on PATH comes from a compiler wrapper such
as ccache.
Bug: https://bugs.gentoo.org/624034

Michał Górny · gentoodev-libs/libclc: Fix possible llvm/clang slot mismatch, #615754Ensure that the LLVM slot with matching clang version is always used.
Otherwise, if you have a newer LLVM slot without clang, and an older
slot with clang, libclc got paths from the newer llvm-config and was
unable to find clang. Now the ebuild finds clang first, and uses
the llvm-config installed alongside it.

Michał Górny · gentoodev-libs/libclc: Respect CXX to fix C++ stdlib incompat, #612582Force using the correct C++ compiler via passing --with-cxx-compiler=
to the configure script. Otherwise, libclc defaults to using clang++
which can cause compatibility issues when clang++ defaults to libc++
and LLVM was built using gcc. This does not affect the compiler used
to build the runtime.